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(-No Model.)

A. A. GRIFPING.

STEAM RADIATOR.

No. 273,066. Patented Feb.27, 1883.

I jaw INVE NTOB:

' WITNESSES:

ATTORNEYS.

UNITED STATES ABNER A. GRIFFING, oFoERsEY CITY, NEW JERSEY.

PATENT OFFICE.

STEAM-RADIATOR.

SPECIFICATION forming part of Letters Patent No. 273,066, dated February27, 1883.

Application filed December 9, 1882- (No model.)

To all whom it may concern:

Be it known that I, ABNER A. GRIFFING, of Jersey City, in the county ofHudson and State of New Jersey, have invented a new and usefulImprovement in Steam-Radiators, of which the following is a full, clear,and exact description.

The object of the invention is to so construct a radiator-tube and itsinterior airpipe that a maximum of heat will be applied to the air as itcirculates through the interior pipes.

Reference is to be had to the accompanying drawings, forming a part ofthis specification, in which similar letters of reference indicatecorresponding parts in all the figures.

Figure 1 is a side elevation, partly sectional, of a radiator with myimprovements. Fig. 2 is a longitudinal section of one of the tubes inlarger size. Fig. 3is a longitudinal section at right angles to Fig. 2.Fig. 4 is a transverse section on line a: 00, and Fig. 5 a transversesection on line 3 3 Fig. 3.

A are the steam-tubes. B is the base,and G the cap, of the radiator. Thetubes A are of flattened or oval form throughout their whole length,except at their upper ends, which are swelled to a circular form. Attheir lower ends they are formed with threaded flanges or bosses at,that are screwed into the upper plate of the base B. Through the centerof the steam-tubes air-tubes 61 pass, these air-tubes being screwed intothe bottom plate of the base B and into the upper ends of the steamtubesA, so as to form internal passages for air from the under side of thebase B to the cap 0. The external diameter of the air-tubes dcorresponds to the internal shorter diameter of the steam-tubes, so thatthere is contact between the exterior surface of the air-tubes and theinterior surface of the steam-tubes, and the steam-tubes are therebydivided into two longitudinal passages for circulation of the steam, thetwo passages being connected at the upper end by the enlargement of thesteam-tubes at that point. By this construction and arrangemeant Iobtain a largely-increased heatiugsurface in proportion to the size ofthe steam-tubes and insure a greater upward circulation of air. I do notlimit myself to this special construction and arrangement, as they maybe varied within the scope of my invention.

1 am aware that air-circulating pipes have been formed in steam orhotwater heating tubes by runuin g two parallel partitions across theinside of a tube laterally open above the bottom for the reception ofair and closely covered at the top, below the top of the tube.

What I claim as new and of my invention 1s- The'combination of aflattened or oval tube, A, swelled out in a circular form at the upperend, with a circular interior air-tube, d, in contact with the sides ofsaid tube A, to form a steam-radiator tube, as shown and described.

ABNER A. GRIFFING. Witnesses:

GEO. D. WALKER, O. SEDGWIGK.

